We have been chasing this for awhile. Maybe fresh eyes will help. We thought this was fixed by obviously not. Spring brakes, drive axle.
Here is the tests...
1. park brake set, service brake off... No leaks anywhere
2. park brake released, service brake off.... bubbles coming out r-6 exhaust hole
3. park brake released, service brake on.... massive leak at exhaust on r-6 and howling noise coming from somewhere.
We have rebuilt this R-6 twice even though it looked new. No change in operation. The shoes are all good. We adjusted the shoes according to directions. The park brake doesn't want to set. Sometimes it does and other times it doesn't. Sometimes the park brake holds, other times it kind of holds. The application pedal doesn't feel as firm as it should, will slowly sink. We have checked for air leaks everywhere and can not find any. The chamber rings don't show any leaks.
The front and boogie brakes seem to be operating right.
So far we have adjusted the brakes, checked for air leaks and don't see any more, rebuilt the R-6, replaced the quick release on the park brakes, replaced the two way check valve for the park brakes.
Any other ideas? short of a match.
Don and Cary
1973 05 Eagle
GM 4107
Neoplan AN340
Replace the R-6 with a R-14 it has the quick release and the anti compound feature built in will save you a bunch of grief the spring brake was a add on with the model of Eagle you own
No telling how it is plumbed some owners get real creative when all it requires is a change in the air direction and a constant air supply when the spring are in the released position when going from the DD3 to spring brakes sounds like you do not have the air supply from the R-6, have some body from the Eagles board send you a schematic for a model 10 forget about the model 05 schematics
good luck
Another test.
We keep thinking that the leak might be inside the brake chamber, so..
Disconnected the anti compounding line from the service line to the two way check valve at the check valve. Released parking brake. Air seeped out the anti compounding line from the service brake chamber. There wasn't any leak coming out the bottom of the R-6. Plugged anti compounding line and the leak reappeared on the R-6. The only way the R-6 got any air was from the park brake being released.
Does this mean that there could be a leak between the parking and service chambers? If the parking chamber is leaking back into the R-6 through the service chamber, would this account for the very slow setting and releasing of the parking brake even though it has a quick release valve?
The R-14 is in our future but afraid that this may not be our problem at the moment.
Don and Cary
1973 05 Eagle
GM 4107
Neoplan AN340
Don -
How many air lines are going to each of the drive axle brake cans? Two or three?
Simple, yet important, clue you've left out to help us help you!
FWIW & HTH. . .
;)
Hi,
They are spring not DD3 chambers. Two air lines not three. The park brake works in reverse, air to release park, exhaust to apply with the valve on the dash.
Don and Cary
1973 05 Eagle
GM 4107
NeoplanAN340
It sounds to me like a leaking brake chamber. I might suggest calling Bendix at 1-800-247-2725 for help diagnosing the issue with the valve. They are very good and do not charge for help.